A panel of experts in civil engineering and geotechnical engineering has completed their investigation into the failure of the slope above Freeway No. 3 in Taiwan last April that killed 4 people. Their forensic geotechnical investigations concluded that the dip slope was already marginally stable. But they noted that they found corroded steel ground anchors that were part of the retaining system meant to restrain the slope. They conjecture that even though the contractor followed the relevant standards at the time of constructions, somehow voids formed around the cable during the grouting process and made the cable susceptible to corrosion.
Also noteworthy is that as a result of this failure, Taiwan’s National Freeway Bureau has changed standards for grouting ground anchors. They also conducted a comprehensive survey of all slopes along freeways and identified 32 slopes that were placed on a priority list for monitoring and inspection and 17 were found to need some form of mitigation. [Source: Taipei Times. Image: Sulekha.com]